Assessment of systolic and diastolic function in clinically healthy horses using ambulatory acoustic cardiography.

This study investigates the use of a noninvasive cardiac monitor, Audicor, in healthily horses for continuous analyses of cardiac mechanical activity and haemodynamics. The research found that using this device for overnight recordings is feasible, providing accurate reference intervals for determining healthy cardiac function in horses.

Background and Objective

• The researchers wanted to find a method to assess cardiac function in horses that did not require special training or equipment and allowed for continuous monitoring. They chose to investigate the use of an acoustic ECG monitor, Audicor, which combines ECG and phonocardiography to calculate indices of cardiac mechanical activity and haemodynamics.

Methods

• The research was a prospective descriptive study in which continuous overnight recordings were obtained from 123 healthy horses.
• The researchers evaluated factors including electromechanical activating time (EMAT), rate-corrected EMATc, left ventricular systolic time (LVST), rate-corrected LVSTc, and the intensity and persistence of the third and fourth heart sounds (S3, S4).

Results

• Of the 123 recordings, Audicor was able to obtain diagnostic quality recordings from 116 horses and produced an artifact-free recording time ranging from about one to fourteen hours, with a mean time of roughly ten and a half hours.
• The researchers found that 44.8% of horses had atrial premature complexes and 4.3% had ventricular premature complexes, but these were a small portion of overall beats.
• Reference intervals for various acoustic cardiography measures were reported, providing a basis for what can be expected in healthy horses. Notably, S3 sounds were graded significantly higher in younger horses compared to older ones.
• The between-day variation in the measures of cardiac function was relatively low, indicating a good reproducibility of the measurement method.

Conclusions

• The study concluded that the Audicor monitor can feasibly be used for overnight recordings in horses for noninvasive and continuous assessment of systolic and diastolic cardiac function.
• While the ECG rhythm analyses require a specialist for over-reading, acoustic cardiography variables are based on automated algorithms that make the process simpler and less subjective.
• Despite some data loss due to technical issues, artifacts, and noise, the study supports further research to ascertain the clinical value of acoustic cardiography in assessing cardiac function in horses.